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Title: Extrinsic Paramagnetic Meissner Effect in Multiphase Indium-Tin Alloys

Abstract

A well-known effect in superconducting materials below their critical temperatures (T{sub c}) is the reduction to zero of their electrical resistivities. Concomitantly, the materials become perfect diamagnets for small fields. This effect, termed the Meissner Effect, allows for the direct measurement of the transition temperature (T{sub c}) by magnetic techniques such as the superconducting quantum interference device (SQUID). A Paramagnetic Meissner Effect (PME), i.e., the unexpected observation of positive magnetic moment in a superconductor below its critical temperature during field cooling (FC), was first reported in 1989 by Svedlindh et al. (1). The origin of PME in high T{sub c} superconductors has been discussed by numerous investigators as possibly resulting from {pi}-junctions, d-wave behavior, giant vortex states, flux compression, or weak links. In conventional superconductors like Nb, the PME was ascribed to the inhomogeneous nature of such samples, whereby their surface is sufficiently different from the interior and becomes superconducting at a higher temperature than the interior on cooling, thereby trapping the magnetic flux. There remains significant controversy regarding the fundamental origin of the PME. Here, we show that the PME in two-phase and three-phase In-Sn alloys is a property resulting from the morphological distribution of the multiple phases. Wemore » propose that PME in these alloys results from microstructural encapsulation of the grains of one superconducting phase inside the grains of another (e.g., the matrix) which has a higher T{sub c}. Hence the PME in this case is extrinsic in nature rather than intrinsic to the material, and could be described as an Extrinsic Paramagnetic Meissner Effect (EPME). It may be expected to occur in multiple-phase alloy samples where more than one of the phases is superconducting, or in nominally single-phase materials where the surface of the specimen, grain boundaries, or other defects have different superconducting properties. This discovery opens the possibility of being able to control the EPME for potential applications in supercomputers, radiation detection, and sensors.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
894798
Report Number(s):
UCRL-JRNL-217541
TRN: US200702%%373
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters, vol. 89, N/A, September 12, 2006, pp. 111903
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ALLOYS; COMPRESSION; CRITICAL TEMPERATURE; DEFECTS; DISTRIBUTION; ENCAPSULATION; GRAIN BOUNDARIES; MAGNETIC FLUX; MAGNETIC MOMENTS; ORIGIN; RADIATION DETECTION; SQUID DEVICES; SUPERCOMPUTERS; SUPERCONDUCTORS; TRANSITION TEMPERATURE; TRAPPING

Citation Formats

Chu, S, Schwartz, A J, Massalski, T B, and Laughlin, D E. Extrinsic Paramagnetic Meissner Effect in Multiphase Indium-Tin Alloys. United States: N. p., 2005. Web.
Chu, S, Schwartz, A J, Massalski, T B, & Laughlin, D E. Extrinsic Paramagnetic Meissner Effect in Multiphase Indium-Tin Alloys. United States.
Chu, S, Schwartz, A J, Massalski, T B, and Laughlin, D E. Fri . "Extrinsic Paramagnetic Meissner Effect in Multiphase Indium-Tin Alloys". United States. doi:. https://www.osti.gov/servlets/purl/894798.
@article{osti_894798,
title = {Extrinsic Paramagnetic Meissner Effect in Multiphase Indium-Tin Alloys},
author = {Chu, S and Schwartz, A J and Massalski, T B and Laughlin, D E},
abstractNote = {A well-known effect in superconducting materials below their critical temperatures (T{sub c}) is the reduction to zero of their electrical resistivities. Concomitantly, the materials become perfect diamagnets for small fields. This effect, termed the Meissner Effect, allows for the direct measurement of the transition temperature (T{sub c}) by magnetic techniques such as the superconducting quantum interference device (SQUID). A Paramagnetic Meissner Effect (PME), i.e., the unexpected observation of positive magnetic moment in a superconductor below its critical temperature during field cooling (FC), was first reported in 1989 by Svedlindh et al. (1). The origin of PME in high T{sub c} superconductors has been discussed by numerous investigators as possibly resulting from {pi}-junctions, d-wave behavior, giant vortex states, flux compression, or weak links. In conventional superconductors like Nb, the PME was ascribed to the inhomogeneous nature of such samples, whereby their surface is sufficiently different from the interior and becomes superconducting at a higher temperature than the interior on cooling, thereby trapping the magnetic flux. There remains significant controversy regarding the fundamental origin of the PME. Here, we show that the PME in two-phase and three-phase In-Sn alloys is a property resulting from the morphological distribution of the multiple phases. We propose that PME in these alloys results from microstructural encapsulation of the grains of one superconducting phase inside the grains of another (e.g., the matrix) which has a higher T{sub c}. Hence the PME in this case is extrinsic in nature rather than intrinsic to the material, and could be described as an Extrinsic Paramagnetic Meissner Effect (EPME). It may be expected to occur in multiple-phase alloy samples where more than one of the phases is superconducting, or in nominally single-phase materials where the surface of the specimen, grain boundaries, or other defects have different superconducting properties. This discovery opens the possibility of being able to control the EPME for potential applications in supercomputers, radiation detection, and sensors.},
doi = {},
journal = {Applied Physics Letters, vol. 89, N/A, September 12, 2006, pp. 111903},
number = ,
volume = ,
place = {United States},
year = {Fri Dec 02 00:00:00 EST 2005},
month = {Fri Dec 02 00:00:00 EST 2005}
}